A Fourier-based algorithm for modelling aberrations in HETE-2's imaging system

The High-Energy Transient Explorer, launched in October 2000, is a satellite experiment dedicated to the study of gamma-ray bursts in a very wide energy range from soft X-ray to gamma-ray wavelengths. The intermediate X-ray range (2-30 keV) is covered by the Wide-field X-ray Monitor (WXM), a coded aperture imager. In this article, an algorithm for reconstructing the positions of gamma-ray bursts is described, which is capable of correcting systematic aberrations to approximately 1' throughout the field of view. Functionality and performance of this algorithm have been validated using data from Monte-Carlo simulations as well as from astrometric observations of the X-ray source Scorpius X-1. (C) 2003 Elsevier Science B.V. All rights reserved.